Term Paper: Striped Bass Recovery in the Hudson

The Hudson River is the second largest estuary on the east coast, and is one of the largest spawning grounds for the striped bass. In the past, however, pollution in the Hudson had caused a drastic reduction in spawning area, and a severe reduction in the number of striped bass within the river. Recently, the Hudson has experienced a recovery in striped bass as a result of pollution reduction efforts, and the consequences of nature. This paper will discuss the recovery of the striped bass in the Hudson, and will show that while the recovery thus far is outstanding, additional efforts are required if the striped bass population is to continue to thrive.

Research has shown that over forty percent of the population of total striped bass comes from the Hudson River. With a spawning area nearly 60 miles in length, one would at first believe the striped bass had a large area in which to breed. However, striped bass require a water salinity range of three to seven parts per thousand to ensure survival of larvae. Due to this, the actual spawning area for striped bass is drastically reduced.

Beginning in 1929, Monsanto, a producer of agricultural products, began to dump a group of industrial chemicals known as PCB's, or polychlorinated biphenyl, into the Hudson as industrial runoff.

By the 1950's, General Electric began using these same chemicals to produce electrical capacitors at two plants, those of Hudson Falls and Fort Edward. Both plants were situated within one mile of one another directly on the Hudson River.

At the time, there were no laws against dumping PCB's into water masses. Thus, GE and other companies on the river legally dumped over one million pounds of PCB's into the Hudson waterway. More came from the fissures in the bedrock beneath the plants. In 1976, the federal government determined these chemicals were endocrine disruptors and neurotoxins, able to cause cancer, interfere with development, and stop reproduction. While the dumping of these toxins was banned in 1976, over seven million pounds existed in the Hudson River.

However, the damage had already been done. By 1977, the sediment in which the chemicals were retained had moved throughout the river. Further, the toxins were found to exist in the fish population, posing a risk to their health as well as to any who might consume the animals. Commercial harvest of striped bass was outlawed in 1977, when the New York Department of Environmental Conservation issued a health warning because of the elevated PCB level within the fish.

PCBs were also found to be persistent within the environment. By the time they were outlawed, the striped bass of the Hudson showed concentrations of the chemicals at five to ten times that of the U.S. Food and Drug Administration's action level of 2 ug/g. Modeling done at the time by scientists at Manhattan College showed PCB concentration would lower by 1995 without any action, but these models failed to take into account the two populations of fish within the river, those of the resident fish, and those of the migratory population..

In addition to the PCB issue, other pollution problems exist within the Hudson. Sewage dumping, industrial discharge, and garbage dumped by citizens has had a negative effect on the ecosystem, as well. In 1996, the New York State Department of Environment Conservation conducted a study again on the PCB concentration of the striped bass in the Hudson. The concentrations reflected a drop in the PCB levels from 3.5 in 1988 to 1.6 in 1996. However, when the study accounted for the two separate populations of striped bass in the Hudson, resident populations were still found to be considerably higher than FDA action levels.

Even as early as 1977, the EPA and other federal agencies began to take steps to help the recovery of the Hudson River. By 1980, Congress passes the Superfund law, which requires toxic waste areas to be effectively cleaned. In 1983, the EPA declared the 200-mile stretch of the river most contaminated as a Superfund site, and by 1989, had begun to push for cleanup.

The new EPA regulations, the construction and repair of industrial plants, and the upgrading of water treatment facilities have remarkably improved the water quality of the Hudson river over the past 30 years. This recovery has led to a remarkable recovery of the striped bass populations within the river as well. As the water quality and water purity at the bottom of the sediment improves, the functioning of the entire ecosystem also improves.

To understand why the recovery of the striped bass in the Hudson is such a remarkable instance, it is vital to understand the fish its self. Striped bass are sensitive animals, and are susceptible to a number of problems. The larvae and younger striped bass are easily killed by changes in water temperature, pH levels, and reduced oxygen levels. Further, these fish do not begin the reproductive cycle until they are five years old. In addition, striped bass migrate annually and are thus exposed to chemicals at various points along their migration route. Any sudden changes in pollutant levels can wipe out entire generations of the fish.

Clearly, when pollution levels are high, pH levels and oxygen levels alter drastically within the river, thereby contributing to the mortality rate and reproductive rate of the striped bass population. As this pollution has been reduced, the water quality has increased proportionately. Today, striped bass of all ages can be found thriving in the Hudson River, and anglers often use catch and release fishing to secure this population base.

However, fish in the upper Hudson, while abundant, still show clear signs of problems. Studies conducted by the University of Maryland indicate the female stripe bass of the Hudson are in increasingly poor health. These studies confirm the problem to be a decline in the lower food chain. The population and nutritional condition of eels, silversides, herring, and menhaden in the Hudson have been drastically reduced by the pollution.

The effects of this are clear. Studies of female striped bass indicate that the greater the fish size, the greater the fertility of the fish. Small bass females lay only 14,000 eggs, whereas those over 50 pounds lay over three and a half million. Further, striped bass larvae feed from a yolk sack until they are two days old. The sack of female striped bass over twenty pounds has a higher food content, thus protecting the larvae for longer periods of time. Further, since the female striped bass returns to their own natal areas to spawn, if that area is highly contaminated, the spawn will be unsuccessful.

There is additional concern about the optimism pertaining to the recovery of the striped bass population. Recruitment efforts such as an increase in food supply has managed to increase the Hudson population, but has increased it with the smaller female bass. The problem with this is that the spawning area of the Hudson, as mentioned, is fairly small for this fish. Large female bass will forfeit their spawning area to smaller females, and will redeposit their eggs, causing the spawn to fail. If this trend continues, the population levels currently achieved will decline, since the spawn results of smaller bass are less than those of the larger fish.

On the other hand, the Hudson River resident population of striped bass have a smaller migration than those of other areas, which has helped the recovery effort of this species. Commercial fishing has been banned in the Hudson of striped bass since 1976, while it has been allowed in New York. Since the striped bass of the Hudson rarely travel beyond the waters of New Jersey, Connecticut, and New York, and since commercial harvest of striped bass is prohibited in two of those states, less fish of the Hudson are killed each year.

When one considers the mortality rate of the striped bass when subjected to commercial fishing, this fact becomes even more important in the recovery of the species in the Hudson. The Hudson stock does not experience wide variations in recruitment. Thus, any mortality rate must be offset by a given recruitment number each year to offset any damage caused by any other event. Current mortality rates of the striped bass population due to natural causes and fishing is approximately.20. Even at this rate, according to the Atlantic States Marine Fisheries Commission, there is only a fifty percent chance of maintaining current population levels.

There is no question that the striped bass of Hudson River have experienced a drastic recovery. With populations reaching record levels in the past ten years, many are considering reopening rights to commercial fishing of the species. With additional cleanup efforts of the EPA and federal government, some believe the recovery will simply continue to increase the population, and improve the overall health of the species within the river.

However, based on studies of striped bass behaviors, nutritional needs, reproductive rates, and recruitment, such a step…
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